VW-exhaust-Manipulation: How VW hid his cheat software – TIME ONLINE

Previously headed the foot on the accelerator and the carburetor as a motor driving. Today do the computer. Motor controls have become so complex that their software would fill 10,000 pages, you wanted to print the code, including descriptions in A4 format.

It is therefore not a problem, something to hide in these thousands of lines of code. For example, a routine that detects when the engine is in the laboratory to be analyzed for the values ​​exhaust gas out. It is also not very difficult to program such a trick. “This is not rocket science that can each manufacturer,” says an expert on motor controls, who prefers to remain anonymous.

But no matter how easy it is thus to manipulate a modern engine, so difficult to discover such interventions is.

The central computer in modern vehicles is ECU or ECM, abbreviations for Engine Control Unit or Electronic Control Module . Short control unit. In the cars from Volkswagen this device sits between the wipers under the windscreen. It collects all the data provided by the sensors of the car – from the turbocharger on the outside temperature or the brakes. Turns the passenger in the passenger compartment, for example, the air conditioner, the control unit ensures that the air compressor starts and that the engine delivers more torque to operate the compressor.

This controller can also detect using sensors data when the car is before an exhaust gas test. Because that is taken from either a so-called roller dynamometer. Front and rear wheels are to the workshop on wheels, the exhaust hangs a thick pipe. When the front wheels spin wildly on the reels, but the rear does not move, the tire sensors provide a unique data pattern.

Thanks to the large number of sensors and the data they read is even seen exactly when the actual exhaust test begins and when it ends. For engine speed, engine temperature, the duration of the driving cycles and different values ​​for the test are laid down in detail. Only when these conditions are always the same, one can compare the emission values ​​of millions of individual cars together. In Europe, all in the so-called “New European Driving Cycle (NEDC)” is regulated in the United States in the “FTP 75″, the Federal Test Procedure .

If you want to outwit the test, you just define in the software of the control unit, such as the various systems of the car are to respond to the test conditions. If the software detects that the test starts, it switches to other, previously programmed settings of the normal mode.

They can pretend that the mixture of fuel is changed to air then for example. More fuel and less air result in less nitrogen oxide – a toxic and hazardous substance whose values ​​in the United States need to be particularly low. The more air is contained, the hotter it gets burned in the combustion chamber and the more of the nitrogen contained in the air. The motor is then no longer as lively, but put to the test that does not matter, there is not about driving pleasure.

Such settings of the software can not be seen, at least not with the normal emission tests. Because the car behaves perfectly normal in the test cycle. In the US, the differences were only noticed because environmentalists of the International Council for Clean Transportation (ICCT) had asked researchers at the University of West Virginia, to compare the test values ​​of some cars with the values ​​for normal road use.